This invention relates generally to a light source for illuminating optical fibers, and more particularly to a lighting device including an arc discharge lamp which provides light output for transmission along a fiber optic bundle or conduit and which is absent significant components of ultraviolet and infrared wave lengths.
Fiber optic bundles are utilized in a wide range of illumination devices and systems for delivering focused light to illuminate various objects for display purposes over an extended period of time. In such circumstances, it is desirable to illuminate these objects with a light emitting from the distal end of the fiber optic bundle which does not include either ultraviolet or infrared wave lengths within the visible light emanating from the fiber optic bundle. The absence of both ultraviolet and infrared components is desirable so as not to accelerate the physical deterioration of objects illuminated by the fiber optic bundle.
U.S. Pat. No. 5,016,152 to Awai is directed to a focused light source which provides an arc discharge lamp positioned within a reflector assembly for focusing light radiation from the lamp and selectively transmits and reflects desirable visible radiation and undesirable ultraviolet and infrared radiation, respectively. The primary purpose is to protect plastic optic fibers from damage. Because the Awai device includes a reflector to accomplish its purpose, a tremendous heat build-up occurs which shortens the life of the arc lamp. Further, the Awai devices does not truly eliminate all infrared radiation from the emanating light.
Other devices for producing a relatively ultraviolet- and infrared-free light utilize a halogen lamp in conjunction with one or more fiber optic bundles. However, these halogen-type lamps are of relatively short life, whereas an arc discharge lamp typically enjoys a useful life of in the range of 12,000 hours if in a properly cooled environment.
The present invention utilizes the longevity of arc discharge lamps in conjunction with a heat sink therearound for dissipating heat build-up. At least one rigid transparent cylindrical member is provided which is specially constructed to filter out ultraviolet wave lengths and to reflect back infrared wave lengths into the heat sink so that the light emitting from the end of the transparent member for use within a fiber optic bundle is substantially free of these undesirable light components within the light spectrum emanating from the arc lamp.